Reading by Design: Evolutionary Psychology and the Neuropsychology of Reading

Article excerpt

A large body of evidence exists which points to the existence of a neural substrate dedicated to reading: (a) neuroimaging (and other) studies which have identified neural regions activated in reading by normal Ss; (b) similar studies on individuals with reading disabilities that show inactivity in those regions; (c) cases of hyperlexia in which preschool children have well-developed word recognition abilities, far beyond their reading comprehension; (d) persons born blind who activate the same neural regions during braille reading as sighted readers do with visual text; (e) similarities between the neuropsychology of language and of reading; and (f) other, similar neural regions which process information that has greater adaptive significance (e.g., an object recognition substrate). Naturalistic evolution would predict there would be no neural tissue dedicated to reading. So this body of research raises questions about the ability of evolution to account for this psychological phenomenon, creates a significa nt problem for evolutionary psychology's theoretical commitment to modularity, and provides an example of psychological evidence that points to intelligent design.

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Reading is arguably one of the most important human neuropsychological processes. Language is, of course, of primordial importance; it articulates human thought and emotion, expresses intimacy, shapes the activity of others, and makes possible the development of the mind and of personhood. Written communication records the mind. All cultures develop over time, but literacy (writing and reading) makes complex cultures possible; without it, cultures are completely dependent upon oral traditions and the limits of human memory. Cumulative cultural information, preserved over time in written form, made the development of economic practices, legal practices, religious practices, literature, philosophy, mathematics, science, and technology possible. So, although the following statement deserves proper qualification (Olson, 1994), the acquisition of literacy (enhanced by the invention of the printing press and now the computer) singularly made possible human culture as we know it today.

But how did humans acquire the cognitive abilities that make literacy possible? Reading is an enormously challenging task requiring the proper functioning of a number of neurological subsystems (and pathways) working extremely quickly in concert, a task that took decades to duplicate in artificial intelligence systems (whereas, conversely, advanced mathematical computations that normal humans cannot perform have been performed by computers for decades). How are we to account for the development in our species of this degree of complexity and speed at the cognitive and neurological levels?

In our culture, naturalistic evolution provides the overwhelmingly influential causal explanatory model for biological life. Although modern psychology has, since its inception, assumed evolution, over the past decade a growing group of psychologists have sought to explain the entire structure of the human mind on the basis of evolutionary principles, and in so doing has developed an influential, new perspective within the field: evolutionary psychology (EP). The main purpose of this article is to see if EP theory coheres well with neuropsychological research on reading.

MODULES AND EVOLUTIONARY PSYCHOLOGY

EP posits that the human mind is composed of hundreds of cognitive mechanisms, called modules, each of which was naturally selected through interaction with the environment within which the first humans arose (the "Environment of Evolutionary Adaptation," EEA). Each mechanism was naturally selected because it contributed to the survival and/or reproduction of the early humans who possessed it. Fodor (1983) was one of the first thinkers influenced by cognitive science to argue that the human brain is organized into a number of "modules" or "input systems. …